Phenol is an important organic chemical with a wide variety of industrial uses. It is used, for example, in the production of phenolic resins, this one use constituting over half the total usage, bisphenol-A, caprolactam and many other materials. A number of processes are currently in use for the production of phenol but the single process providing the largest proportion of the total production capacity is the cumene process which now accounts for over three quarters of the total U.S. production. The basic reaction involved in this process is the cleavage of cumene hydroperoxide into phenol and acetone: EQU C.sub.6 H.sub.5.C(CH.sub.3).sub.2 OOH=C.sub.6 H.sub.5 OH+(CH.sub.3).sub.2 CO
The reaction takes place under acid conditions with the yield of both phenol and acetone generally being 40 percent or more.
On the industrial scale, the cumene hydroperoxide is usually treated with dilute sulphuric acid (5 to 25 percent concentration) at a temperature of about 50.degree. to 70.degree. C. After the cleavage is complete, the reaction mixture is separated and the oil layer distilled to obtain the phenol and acetone together with cumene, alpha-methylstyrene, acetophenone and tars. The cumene may be recycled for conversion to the hydroperoxide and subsequent cleavage. The phenol produced in this way is suitable for use in resins although further purification is required for a pharmaceutical grade product.
Although the process described above is capable of producing both phenol and acetone in good yields, it would be desirable to find a process which would reduce the need for the product separation and purification steps which are consequent upon a homogeneous process of that kind.
The heterogenous cleavage of cumene hydroperoxide (CHP) over various acidic solids has already been reported. For example, the use of amorphous aluminosilicates for this purpose is described in J. Macromol Sci-Chem. A5(5), 995-1005, August 1971 and U.S. Pat. No. 3,305,590 describes the use of silica-alumina composites in this reaction. The use of silica-alumina gels is also described in Stud. Univ. Babes-Bolyai Ch. 16(1), 61-67(1971). Other materials whose utility as catalysts for this reaction include various zeolites such as sillimanite, as described in Zh. Prikl. Khim 54, No. 8, 1793-9 (1981) and zeolites X and Y in certain cationic forms, as reported in Z. Chem. 15 Jg. (1975) 152-153 (Heft 4). The decomposition of other peroxides over zeolites X and Y is reported in Collection Czechoslov. Chem. Commun Vol. 40, 865-874 (1975).